The sale of an idyllic Greek island owned for decades by the Onassis family has been thrown into doubt amid concerns that it contravenes the wishes of the late shipping tycoon Aristotle Onassis. Skorpios, a forested island surrounded by the crystal clear waters of the Ionian Sea, was sold last month by the magnate's granddaughter, 28-year-old Athina Onassis Roussel, to a Russian oligarch, Dmitry Rybolovlev, for a reported $100 million (£66 million). Mr Rybolovlev, 47, the multi-billionaire owner of the AS Monaco Football Club and co-founder of Uralkali, a Russian potash producer, bought it as an extravagant gift for his 24-year-old socialite daughter, Ekaterina. But the deal is now in question amid claims that Onassis, who is buried on the island, stipulated in his will that it should remain in his family's hands as long as they could afford to maintain it. Failing that, the island was to be bequeathed either to the nation, to be used as a holiday retreat by the head of state,